According to the search results, hostile mobs in Minecraft require a light level of 0 to spawn since the 1.18 Caves and Cliffs Part 2 update. This means that even if a block has a light level of 1, no hostile mob can spawn on that block. Before this update, the light level for hostile mob spawning was 7 or below. It is important to note that there are two types of light levels in Minecraft: block light level and sky light level. Block light level is created by artificial light sources, like torches, and will block spawns at level 1 or higher. Sky light level is the light level from being exposed to the sky (or being near such a block), and only blocks spawns if it is at level 8 or higher.

In summary, hostile mobs spawn in Minecraft at a light level of 0 or lower, which means that players dont need to spam torches everywhere to keep their builds safe from hostile mobs.